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Dehnel J, Harchol A, Barak Y, Meir I, Horani F, Shapiro A, Strassberg R, de Mello Donegá C, Demir HV, Gamelin DR, Sharma K, Lifshitz E. Optically detected magnetic resonance spectroscopic analyses on the role of magnetic ions in colloidal nanocrystals. J Chem Phys 2023; 159:071001. [PMID: 37581419 DOI: 10.1063/5.0160787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023] Open
Abstract
Incorporating magnetic ions into semiconductor nanocrystals has emerged as a prominent research field for manipulating spin-related properties. The magnetic ions within the host semiconductor experience spin-exchange interactions with photogenerated carriers and are often involved in the recombination routes, stimulating special magneto-optical effects. The current account presents a comparative study, emphasizing the impact of engineering nanostructures and selecting magnetic ions in shaping carrier-magnetic ion interactions. Various host materials, including the II-VI group, halide perovskites, and I-III-VI2 in diverse structural configurations such as core/shell quantum dots, seeded nanorods, and nanoplatelets, incorporated with magnetic ions such as Mn2+, Ni2+, and Cu1+/2+ are highlighted. These materials have recently been investigated by us using state-of-the-art steady-state and transient optically detected magnetic resonance (ODMR) spectroscopy to explore individual spin-dynamics between the photogenerated carriers and magnetic ions and their dependence on morphology, location, crystal composition, and type of the magnetic ion. The information extracted from the analyses of the ODMR spectra in those studies exposes fundamental physical parameters, such as g-factors, exchange coupling constants, and hyperfine interactions, together providing insights into the nature of the carrier (electron, hole, dopant), its local surroundings (isotropic/anisotropic), and spin dynamics. The findings illuminate the importance of ODMR spectroscopy in advancing our understanding of the role of magnetic ions in semiconductor nanocrystals and offer valuable knowledge for designing magnetic materials intended for various spin-related technologies.
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Affiliation(s)
- Joanna Dehnel
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Adi Harchol
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yahel Barak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Itay Meir
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Faris Horani
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
| | - Arthur Shapiro
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Optical Materials Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Rotem Strassberg
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Celso de Mello Donegá
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Hilmi Volkan Demir
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering, Nanyang Technological University-NTU Singapore, 639798, Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800, Türkiye
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
| | - Kusha Sharma
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Efrat Lifshitz
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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Kagan CR, Bassett LC, Murray CB, Thompson SM. Colloidal Quantum Dots as Platforms for Quantum Information Science. Chem Rev 2020; 121:3186-3233. [DOI: 10.1021/acs.chemrev.0c00831] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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3
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Sarang S, Delmas W, Bonabi Naghadeh S, Cherrette V, Zhang JZ, Ghosh S. Low-Temperature Energy Transfer via Self-Trapped Excitons in Mn 2+-Doped 2D Organometal Halide Perovskites. J Phys Chem Lett 2020; 11:10368-10374. [PMID: 33236909 DOI: 10.1021/acs.jpclett.0c03287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We investigate the mechanisms of energy transfer in Mn2+-doped ethylammonium lead bromide (EA2PbBr4:Mn2+), a two-dimensional layered perovskite (2DLP), using cryogenic optical spectroscopy. At temperature T > 120 K, photoluminescence (PL) is dominated by emission from Mn2+, with complete suppression of band edge (BE) emission and self-trapped exciton (STE) emission. However, for T < 120 K, in addition to Mn2+ emission, PL is observed from BE and STEs. Data further reveal that for 20 K < T < 120 K, STEs form the most dominant routes in assisting energy transfer (ET) from 2DLP to Mn2+ dopants. However, at higher Mn2+ concentration, higher activation energies indicate defect states come into play, successfully competing with STEs for ET both from BE to STE states and from STE to Mn2+. Finally, using polarization-resolved spectroscopy, we demonstrate optical spin orientation of the Mn2+ ions via ET from 2DLP excitons at zero magnetic field. Our results reveal fundamental insights on the interactions between quantum confined charge carriers and dopants in organometal halide perovskites.
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Affiliation(s)
- Som Sarang
- Department of Physics, School of Natural Sciences, University of California, Merced, California 95343, United States
| | - William Delmas
- Department of Physics, School of Natural Sciences, University of California, Merced, California 95343, United States
| | - Sara Bonabi Naghadeh
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Vivien Cherrette
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Jin Z Zhang
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Sayantani Ghosh
- Department of Physics, School of Natural Sciences, University of California, Merced, California 95343, United States
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Dehnel J, Barak Y, Meir I, Budniak AK, Nagvenkar AP, Gamelin DR, Lifshitz E. Insight into the Spin Properties in Undoped and Mn-Doped CdSe/CdS-Seeded Nanorods by Optically Detected Magnetic Resonance. ACS NANO 2020; 14:13478-13490. [PMID: 32935976 DOI: 10.1021/acsnano.0c05454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Controlling the spin degrees of freedom of photogenerated species in semiconductor nanostructures via magnetic doping is an emerging scientific field that may play an important role in the development of new spin-based technologies. The current work explores spin properties in colloidal CdSe/CdS:Mn seeded-nanorod structures doped with a dilute concentration of Mn2+ ions across the rods. The spin properties were determined using continuous-wave optically detected magnetic resonance (ODMR) spectroscopy recorded under variable microwave chopping frequencies. These experiments enabled the deconvolution of a few different radiative recombination processes: band-to-band, trap-to-band, and trap-to-trap emission. The results uncovered the major role of carrier trapping on the spin properties of elongated structures. The magnetic parameters, determined through spin-Hamiltonian simulation of the steady-state ODMR spectra, reflect anisotropy associated with carrier trapping at the seed/rod interface. These observations unveiled changes in the carriers' g-factors and spin-exchange coupling constants as well as extension of radiative and spin-lattice relaxation times due to magnetic coupling between interface carriers and neighboring Mn2+ ions. Overall, this work highlights that the spin degrees of freedom in seeded nanorods are governed by interfacial trapping and can be further manipulated by magnetic doping. These results provide insights into anisotropic nanostructure spin properties relevant to future spin-based technologies.
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Affiliation(s)
- Joanna Dehnel
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yahel Barak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Itay Meir
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Adam K Budniak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Anjani P Nagvenkar
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Daniel R Gamelin
- Department of Chemistry and the Molecular Engineering Materials Center, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Efrat Lifshitz
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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5
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Bogucki A, Zinkiewicz Ł, Grzeszczyk M, Pacuski W, Nogajewski K, Kazimierczuk T, Rodek A, Suffczyński J, Watanabe K, Taniguchi T, Wasylczyk P, Potemski M, Kossacki P. Ultra-long-working-distance spectroscopy of single nanostructures with aspherical solid immersion microlenses. LIGHT, SCIENCE & APPLICATIONS 2020; 9:48. [PMID: 32257179 PMCID: PMC7101340 DOI: 10.1038/s41377-020-0284-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 02/25/2020] [Accepted: 03/05/2020] [Indexed: 06/08/2023]
Abstract
In light science and applications, equally important roles are played by efficient light emitters/detectors and by the optical elements responsible for light extraction and delivery. The latter should be simple, cost effective, broadband, versatile and compatible with other components of widely desired micro-optical systems. Ideally, they should also operate without high-numerical-aperture optics. Here, we demonstrate that all these requirements can be met with elliptical microlenses 3D printed on top of light emitters. Importantly, the microlenses we propose readily form the collected light into an ultra-low divergence beam (half-angle divergence below 1°) perfectly suited for ultra-long-working-distance optical measurements (600 mm with a 1-inch collection lens), which are not accessible to date with other spectroscopic techniques. Our microlenses can be fabricated on a wide variety of samples, including semiconductor quantum dots and fragile van der Waals heterostructures made of novel two-dimensional materials, such as monolayer and few-layer transition metal dichalcogenides.
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Affiliation(s)
- Aleksander Bogucki
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Łukasz Zinkiewicz
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | | | - Wojciech Pacuski
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Karol Nogajewski
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Tomasz Kazimierczuk
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Aleksander Rodek
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Jan Suffczyński
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 Japan
| | - Piotr Wasylczyk
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Marek Potemski
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, avenue des Martyrs 25, 38042 Grenoble, France
| | - Piotr Kossacki
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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6
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Lorenz S, Erickson CS, Riesner M, Gamelin DR, Fainblat R, Bacher G. Directed Exciton Magnetic Polaron Formation in a Single Colloidal Mn 2+:CdSe/CdS Quantum Dot. NANO LETTERS 2020; 20:1896-1906. [PMID: 31999124 DOI: 10.1021/acs.nanolett.9b05136] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
One of the most prominent signatures of transition-metal doping in colloidal nanocrystals is the formation of charge carrier-induced magnetization of the dopant spin sublattice, called exciton magnetic polaron (EMP). Understanding the direction of EMP formation, however, is still a major obstacle. Here, we present a series of temperature-dependent photoluminescence studies on single colloidal Mn2+:CdSe/CdS core/shell quantum dots (QDs) performed in a vector magnetic field providing a unique insight into the interaction between individual excitons and numerous magnetic impurities. The energy of the QD emission and its full width at half-maximum are controlled by the interplay of EMP formation and statistical magnetic fluctuations, in excellent agreement with theory. Most important, we give the first direct demonstration that anisotropy effects-hypothesized for more than a decade-dominate the direction of EMP formation. Our findings reveal a pathway for directing the orientation of optically induced magnetization in colloidal nanocrystals.
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Affiliation(s)
- Severin Lorenz
- Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstr. 81, Duisburg 47057 Germany
| | - Christian S Erickson
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Maurizio Riesner
- Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstr. 81, Duisburg 47057 Germany
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Rachel Fainblat
- Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstr. 81, Duisburg 47057 Germany
| | - Gerd Bacher
- Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstr. 81, Duisburg 47057 Germany
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7
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Rodek A, Kazimierczuk T, Bogucki A, Smoleński T, Pacuski W, Kossacki P. Readout of a dopant spin in the anisotropic quantum dot with a single magnetic ion. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:455301. [PMID: 31323648 DOI: 10.1088/1361-648x/ab33d9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Owing to exchange interaction between the exciton and magnetic ion, a quantum dot embedding a single magnetic ion is a great platform for optical control of individual spin. In particular, a quantum dot provides strong and sharp optical transitions, which give experimental access to spin states of an individual magnetic ion. We show, however, that physics of quantum dot excitons also complicate spin readout and optical spin manipulation in such a system. This is due to electron-hole exchange interaction in anisotropic quantum dots, which affects the polarisation of the emission lines. One of the consequences is that the intensity of spectral lines in a single spectrum are not simply proportional to the population of various spin states of magnetic ion. In order to provide a solution of the above problem, we present a method of extracting both the spin polarisation degree of a neutral exciton and magnetic dopant inside a semiconductor quantum dot in an external magnetic field. Our approach is experimentally verified on a system of CdSe/ZnSe quantum dot containing a single Fe2+ ion. Both the resonant and non-resonant excitation regimes are explored resulting in a record high optical orientation efficiency of dopant spin in the former case. The proposed solutions can be easily expanded to any other system of quantum dots containing magnetic dopants.
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Affiliation(s)
- A Rodek
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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8
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Strassberg R, Delikanli S, Barak Y, Dehnel J, Kostadinov A, Maikov G, Hernandez-Martinez PL, Sharma M, Demir HV, Lifshitz E. Persuasive Evidence for Electron-Nuclear Coupling in Diluted Magnetic Colloidal Nanoplatelets Using Optically Detected Magnetic Resonance Spectroscopy. J Phys Chem Lett 2019; 10:4437-4447. [PMID: 31314537 DOI: 10.1021/acs.jpclett.9b01999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The incorporation of magnetic impurities into semiconductor nanocrystals with size confinement promotes enhanced spin exchange interaction between photogenerated carriers and the guest spins. This interaction stimulates new magneto-optical properties with significant advantages for emerging spin-based technologies. Here we observe and elaborate on carrier-guest interactions in magnetically doped colloidal nanoplatelets with the chemical formula CdSe/Cd1-xMnxS, explored by optically detected magnetic resonance and magneto-photoluminescence spectroscopy. The host matrix, with a quasi-type II electronic configuration, introduces a dominant interaction between a photogenerated electron and a magnetic dopant. Furthermore, the data convincingly presents the interaction between an electron and nuclear spins of the doped ions located at neighboring surroundings, with consequent influence on the carrier's spin relaxation time. The nuclear spin contribution by the magnetic dopants in colloidal nanoplatelets is considered here for the first time.
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Affiliation(s)
- Rotem Strassberg
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Savas Delikanli
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering , Nanyang Technological University-NTU Singapore , 639798 Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology , Bilkent University , Ankara 06800 , Turkey
| | - Yahel Barak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Joanna Dehnel
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Alyssa Kostadinov
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Georgy Maikov
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Pedro Ludwig Hernandez-Martinez
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering , Nanyang Technological University-NTU Singapore , 639798 Singapore
| | - Manoj Sharma
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering , Nanyang Technological University-NTU Singapore , 639798 Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology , Bilkent University , Ankara 06800 , Turkey
| | - Hilmi Volkan Demir
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering , Nanyang Technological University-NTU Singapore , 639798 Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology , Bilkent University , Ankara 06800 , Turkey
| | - Efrat Lifshitz
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
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9
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Electric field tuning of spin splitting in topological insulator quantum dots doped with a single magnetic ion. Sci Rep 2019; 9:9080. [PMID: 31235703 PMCID: PMC6591290 DOI: 10.1038/s41598-019-45067-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/14/2019] [Indexed: 11/17/2022] Open
Abstract
We investigate theoretically the electron spin states in a disk-shaped topological insulator quantum dot (TIQD) containing a single magnetic Mn2+ ion. We demonstrate that the energy spectra and the density distributions of the symmetry-protected edge states in a HgTe TIQD can be modulated effectively by a single magnetic impurity Mn2+. Additionally, when an in-plane external electric field is applied., it not only tunes the spin splittings of edge states via the s(p)-d exchange interaction between the electron (hole) and the magnetic Mn2+ ion respectively, but also gives rise to the bright-to-dark transitions in the optical transition spectrum. Such spin properties of TIQDs with single Mn2+ ion as illustrated in this work could offer a new platform for topological electro-optical devices.
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10
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Smoleński T, Cywiński Ł, Kossacki P. Mechanisms of optical orientation of an individual Mn 2+ ion spin in a II-VI quantum dot. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:055303. [PMID: 29315081 DOI: 10.1088/1361-648x/aaa20c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We provide a theoretical description of the optical orientation of a single Mn2+ ion spin under quasi-resonant excitation demonstrated experimentally by Goryca et al (2009 Phys. Rev. Lett. 103 087401). We build and analyze a hierarchy of models by starting with the simplest assumptions (transfer of perfectly spin-polarized excitons from Mn-free dot to the other dot containing a single Mn2+ spin, followed by radiative recombination) and subsequently adding more features, such as spin relaxation of electrons and holes. Particular attention is paid to the role of the influx of the dark excitons and the process of biexciton formation, which are shown to contribute significantly to the orientation process in the quasi-resonant excitation case. Analyzed scenarios show how multiple features of the excitonic complexes in magnetically-doped quantum dots, such as the values of exchange integrals, spin relaxation times, etc, lead to a plethora of optical orientation processes, characterized by distinct dependencies on light polarization and laser intensity, and occurring on distinct timescales. Comparison with experimental data shows that the correct description of the optical orientation mechanism requires taking into account Mn2+ spin-flip processes occurring not only when the exciton is already in the orbital ground state of the light-emitting dot, but also those that happen during the exciton transfer from high-energy states to the ground state. Inspired by the experimental results on energy relaxation of electrons and holes in nonmagnetic dots, we focus on the process of biexciton creation allowed by mutual spin-flip of an electron and the Mn2+ spin, and we show that by including it in the model, we obtain good qualitative and quantitative agreement with the experimental data on quasi-resonantly driven Mn2+ spin orientation.
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Affiliation(s)
- T Smoleński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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11
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Pradhan N, Das Adhikari S, Nag A, Sarma DD. Luminescence, Plasmonic, and Magnetic Properties of Doped Semiconductor Nanocrystals. Angew Chem Int Ed Engl 2017; 56:7038-7054. [DOI: 10.1002/anie.201611526] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/18/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Narayan Pradhan
- Department of Materials Science; Indian Association for the Cultivation of Science; Kolkata 700032 India
| | - Samrat Das Adhikari
- Department of Materials Science; Indian Association for the Cultivation of Science; Kolkata 700032 India
| | - Angshuman Nag
- Department of Chemistry and Centre for Energy Science; Indian Institute of Science Education and Research, IISER; Pune 411008 India
| | - D. D. Sarma
- Solid State and Structural Chemistry Unit; Indian Institute of Science; Bengaluru 560012 India
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12
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Pradhan N, Das Adhikari S, Nag A, Sarma DD. Dotierte Halbleiter-Nanokristalle: Lumineszenz, plasmonische und magnetische Eigenschaften. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611526] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Narayan Pradhan
- Department of Materials Science; Indian Association for the Cultivation of Science; Kolkata 700032 Indien
| | - Samrat Das Adhikari
- Department of Materials Science; Indian Association for the Cultivation of Science; Kolkata 700032 Indien
| | - Angshuman Nag
- Department of Chemistry and Centre for Energy Science; Indian Institute of Science Education and Research, IISER; Pune 411008 Indien
| | - D. D. Sarma
- Solid State and Structural Chemistry Unit; Indian Institute of Science; Bengaluru 560012 Indien
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Rice WD, Liu W, Pinchetti V, Yakovlev DR, Klimov VI, Crooker SA. Direct Measurements of Magnetic Polarons in Cd 1-xMn xSe Nanocrystals from Resonant Photoluminescence. NANO LETTERS 2017; 17:3068-3075. [PMID: 28388078 DOI: 10.1021/acs.nanolett.7b00421] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In semiconductors, quantum confinement can greatly enhance the interaction between band carriers (electrons and holes) and dopant atoms. One manifestation of this enhancement is the increased stability of exciton magnetic polarons in magnetically doped nanostructures. In the limit of very strong 0D confinement that is realized in colloidal semiconductor nanocrystals, a single exciton can exert an effective exchange field Bex on the embedded magnetic dopants that exceeds several tesla. Here we use the very sensitive method of resonant photoluminescence (PL) to directly measure the presence and properties of exciton magnetic polarons in colloidal Cd1-xMnxSe nanocrystals. Despite small Mn2+ concentrations (x = 0.4-1.6%), large polaron binding energies up to ∼26 meV are observed at low temperatures via the substantial Stokes shift between the pump laser and the resonant PL maximum, indicating nearly complete alignment of all Mn2+ spins by Bex. Temperature and magnetic field-dependent studies reveal that Bex ≈ 10 T in these nanocrystals, in good agreement with theoretical estimates. Further, the emission line widths provide direct insight into the statistical fluctuations of the Mn2+ spins. These resonant PL studies provide detailed insight into collective magnetic phenomena, especially in lightly doped nanocrystals where conventional techniques such as nonresonant PL or time-resolved PL provide ambiguous results.
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Affiliation(s)
- W D Rice
- Department of Physics and Astronomy, University of Wyoming , Laramie, Wyoming 82071, United States
| | | | - V Pinchetti
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca , Via Cozzi 55, IT-20125 Milano, Italy
| | - D R Yakovlev
- Experimentelle Physik 2, Technische Universität Dortmund , D-44221 Dortmund, Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
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14
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de Assis PL, Yeo I, Gloppe A, Nguyen HA, Tumanov D, Dupont-Ferrier E, Malik NS, Dupuy E, Claudon J, Gérard JM, Auffèves A, Arcizet O, Richard M, Poizat JP. Strain-Gradient Position Mapping of Semiconductor Quantum Dots. PHYSICAL REVIEW LETTERS 2017; 118:117401. [PMID: 28368631 DOI: 10.1103/physrevlett.118.117401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Indexed: 06/07/2023]
Abstract
We introduce a nondestructive method to determine the position of randomly distributed semiconductor quantum dots (QDs) integrated in a solid photonic structure. By setting the structure in an oscillating motion, we generate a large stress gradient across the QDs plane. We then exploit the fact that the QDs emission frequency is highly sensitive to the local material stress to map the position of QDs deeply embedded in a photonic wire antenna with an accuracy ranging from ±35 nm down to ±1 nm. In the context of fast developing quantum technologies, this technique can be generalized to different photonic nanostructures embedding any stress-sensitive quantum emitters.
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Affiliation(s)
- P-L de Assis
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - I Yeo
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
- INAC-PHELIQS, "Nanophysique et semiconducteurs" group, CEA, Univ. Grenoble Alpes, France
| | - A Gloppe
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
| | - H A Nguyen
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
| | - D Tumanov
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
| | | | - N S Malik
- INAC-PHELIQS, "Nanophysique et semiconducteurs" group, CEA, Univ. Grenoble Alpes, France
| | - E Dupuy
- INAC-PHELIQS, "Nanophysique et semiconducteurs" group, CEA, Univ. Grenoble Alpes, France
| | - J Claudon
- INAC-PHELIQS, "Nanophysique et semiconducteurs" group, CEA, Univ. Grenoble Alpes, France
| | - J-M Gérard
- INAC-PHELIQS, "Nanophysique et semiconducteurs" group, CEA, Univ. Grenoble Alpes, France
| | - A Auffèves
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
| | - O Arcizet
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
| | - M Richard
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
| | - J-Ph Poizat
- Institut NEEL, CNRS, Univ. Grenoble Alpes, France
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15
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Fainblat R, Barrows CJ, Hopmann E, Siebeneicher S, Vlaskin VA, Gamelin DR, Bacher G. Giant Excitonic Exchange Splittings at Zero Field in Single Colloidal CdSe Quantum Dots Doped with Individual Mn 2+ Impurities. NANO LETTERS 2016; 16:6371-6377. [PMID: 27646931 DOI: 10.1021/acs.nanolett.6b02775] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Replacing a single atom of a host semiconductor nanocrystal with a functional dopant can introduce completely new properties potentially valuable for "solotronic" information-processing applications. Here, we report successful doping of colloidal CdSe quantum dots with a very small number of manganese ions-down to the ultimate limit of one. Single-particle spectroscopy reveals spectral fingerprints of the spin-spin interactions between individual dopants and quantum-dot excitons. Spectrally well-resolved emission peaks are observed that can be related to the discrete spin projections of individual Mn2+ ions. In agreement with theoretical predictions, the exchange splittings are enhanced by more than an order of magnitude in these quantum dots compared to their epitaxial counterparts, opening a path for solotronic applications at elevated temperatures.
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Affiliation(s)
- Rachel Fainblat
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , Bismarckstr. 81, Duisburg, 47057 Germany
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Charles J Barrows
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Eric Hopmann
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , Bismarckstr. 81, Duisburg, 47057 Germany
| | - Simon Siebeneicher
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , Bismarckstr. 81, Duisburg, 47057 Germany
| | - Vladmir A Vlaskin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Gerd Bacher
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , Bismarckstr. 81, Duisburg, 47057 Germany
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16
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Muckel F, Yang J, Lorenz S, Baek W, Chang H, Hyeon T, Bacher G, Fainblat R. Digital Doping in Magic-Sized CdSe Clusters. ACS NANO 2016; 10:7135-41. [PMID: 27420556 DOI: 10.1021/acsnano.6b03348] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Magic-sized semiconductor clusters represent an exciting class of materials located at the boundary between quantum dots and molecules. It is expected that replacing single atoms of the host crystal with individual dopants in a one-by-one fashion can lead to unique modifications of the material properties. Here, we demonstrate the dependence of the magneto-optical response of (CdSe)13 clusters on the discrete number of Mn(2+) ion dopants. Using time-of-flight mass spectrometry, we are able to distinguish undoped, monodoped, and bidoped cluster species, allowing for an extraction of the relative amount of each species for a specific average doping concentration. A giant magneto-optical response is observed up to room temperature with clear evidence that exclusively monodoped clusters are magneto-optically active, whereas the Mn(2+) ions in bidoped clusters couple antiferromagnetically and are magneto-optically passive. Mn(2+)-doped clusters therefore represent a system where magneto-optical functionality is caused by solitary dopants, which might be beneficial for future solotronic applications.
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Affiliation(s)
- Franziska Muckel
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , Bismarckstraße 81, 47057 Duisburg, Germany
| | - Jiwoong Yang
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University , Seoul 08826, Republic of Korea
| | - Severin Lorenz
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , Bismarckstraße 81, 47057 Duisburg, Germany
| | - Woonhyuk Baek
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University , Seoul 08826, Republic of Korea
| | - Hogeun Chang
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University , Seoul 08826, Republic of Korea
| | - Taeghwan Hyeon
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University , Seoul 08826, Republic of Korea
| | - Gerd Bacher
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , Bismarckstraße 81, 47057 Duisburg, Germany
| | - Rachel Fainblat
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , Bismarckstraße 81, 47057 Duisburg, Germany
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University , Seoul 08826, Republic of Korea
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17
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Rice WD, Liu W, Baker TA, Sinitsyn NA, Klimov VI, Crooker SA. Revealing giant internal magnetic fields due to spin fluctuations in magnetically doped colloidal nanocrystals. NATURE NANOTECHNOLOGY 2016; 11:137-142. [PMID: 26595331 DOI: 10.1038/nnano.2015.258] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/06/2015] [Indexed: 06/05/2023]
Abstract
Strong quantum confinement in semiconductors can compress the wavefunctions of band electrons and holes to nanometre-scale volumes, significantly enhancing interactions between themselves and individual dopants. In magnetically doped semiconductors, where paramagnetic dopants (such as Mn(2+), Co(2+) and so on) couple to band carriers via strong sp-d spin exchange, giant magneto-optical effects can therefore be realized in confined geometries using few or even single impurity spins. Importantly, however, thermodynamic spin fluctuations become increasingly relevant in this few-spin limit. In nanoscale volumes, the statistical fluctuations of N spins are expected to generate giant effective magnetic fields Beff, which should dramatically impact carrier spin dynamics, even in the absence of any applied field. Here we directly and unambiguously reveal the large Beff that exist in Mn(2+)-doped CdSe colloidal nanocrystals using ultrafast optical spectroscopy. At zero applied magnetic field, extremely rapid (300-600 GHz) spin precession of photoinjected electrons is observed, indicating Beff ∼ 15 -30 T for electrons. Precession frequencies exceed 2 THz in applied magnetic fields. These signals arise from electron precession about the random fields due to statistically incomplete cancellation of the embedded Mn(2+) moments, thereby revealing the initial coherent dynamics of magnetic polaron formation, and highlighting the importance of magnetization fluctuations on carrier spin dynamics in nanomaterials.
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Affiliation(s)
- William D Rice
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Wenyong Liu
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Thomas A Baker
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Nikolai A Sinitsyn
- Theory Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Victor I Klimov
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Scott A Crooker
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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18
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Smoleński T, Kazimierczuk T, Kobak J, Goryca M, Golnik A, Kossacki P, Pacuski W. Magnetic ground state of an individual Fe(2+) ion in strained semiconductor nanostructure. Nat Commun 2016; 7:10484. [PMID: 26818580 PMCID: PMC4738340 DOI: 10.1038/ncomms10484] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 12/17/2015] [Indexed: 11/15/2022] Open
Abstract
Single impurities with nonzero spin and multiple ground states offer a degree of freedom that can be utilized to store the quantum information. However, Fe(2+) dopant is known for having a single nondegenerate ground state in the bulk host semiconductors and thus is of little use for spintronic applications. Here we show that the well-established picture of Fe(2+) spin configuration can be modified by subjecting the Fe(2+) ion to high strain, for example, produced by lattice mismatched epitaxial nanostructures. Our analysis reveals that high strain induces qualitative change in the ion energy spectrum and results in nearly doubly degenerate ground state with spin projection Sz= ± 2. We provide an experimental proof of this concept using a new system: a strained epitaxial quantum dot containing individual Fe(2+) ion. Magnetic character of the Fe(2+) ground state in a CdSe/ZnSe dot is revealed in photoluminescence experiments by exploiting a coupling between a confined exciton and the single-iron impurity. We also demonstrate that the Fe(2+) spin can be oriented by spin-polarized excitons, which opens a possibility of using it as an optically controllable two-level system free of nuclear spin fluctuations.
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Affiliation(s)
- T. Smoleński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - T. Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - J. Kobak
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - M. Goryca
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - A. Golnik
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - P. Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - W. Pacuski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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19
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Niu P, Shi YL, Sun Z, Nie YH, Luo HG. Kondo peak splitting and Kondo dip induced by a local moment. Sci Rep 2015; 5:18021. [PMID: 26658128 PMCID: PMC4675084 DOI: 10.1038/srep18021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/10/2015] [Indexed: 11/09/2022] Open
Abstract
Many features like spin-orbit coupling, bias and magnetic fields applied, and so on, can strongly influence the Kondo effect. One of the consequences is Kondo peak splitting. However, Kondo peak splitting led by a local moment has not been investigated systematically. In this research we study theoretically electronic transport through a single-level quantum dot exchange coupled to a local magnetic moment in the Kondo regime. We focus on the Kondo peak splitting induced by an anisotropic exchange coupling between the quantum dot and the local moment, which shows rich splitting behavior. We consider the cases of a local moment with S = 1/2 and S = 1. The longitudinal (z-component) coupling plays a role of multivalued magnetic fields and the transverse (x, y-components) coupling lifts the degeneracy of the quantum dot, both of which account for the fine Kondo peak splitting structures. The inter-level or intra-level transition processes are identified in detail. Moreover, we find a Kondo dip at the Fermi level under the proper parameters. The possible experimental observations of these theoretical results should deepen our understanding of Kondo physics.
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Affiliation(s)
- Pengbin Niu
- Institute of Solid State Physics and Department of Physics, Shanxi Datong University, Datong 037009, China.,Shanxi Provincial Key Laboratory of micro-structural electromagnetic functional materials, Datong 037009, China
| | - Yun-Long Shi
- Institute of Solid State Physics and Department of Physics, Shanxi Datong University, Datong 037009, China
| | - Zhu Sun
- Institute of Solid State Physics and Department of Physics, Shanxi Datong University, Datong 037009, China
| | - Yi-Hang Nie
- Institute of Theoretical Physics, Shanxi University, Taiyuan 030006, China
| | - Hong-Gang Luo
- Center for Interdisciplinary Studies &Key Laboratory for Magnetism and Magnetic Materials of the MoE, Lanzhou University, Lanzhou 730000, China.,Beijing Computational Science Research Center, Beijing 100084, China
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20
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Nelson HD, Bradshaw LR, Barrows CJ, Vlaskin VA, Gamelin DR. Picosecond Dynamics of Excitonic Magnetic Polarons in Colloidal Diffusion-Doped Cd(1-x)Mn(x)Se Quantum Dots. ACS NANO 2015; 9:11177-11191. [PMID: 26417918 DOI: 10.1021/acsnano.5b04719] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Spontaneous magnetization is observed at zero magnetic field in photoexcited colloidal Cd(1-x)Mn(x)Se (x = 0.13) quantum dots (QDs) prepared by diffusion doping, reflecting strong Mn(2+)-exciton exchange coupling. The picosecond dynamics of this phenomenon, known as an excitonic magnetic polaron (EMP), are examined using a combination of time-resolved photoluminescence, magneto-photoluminescence, and Faraday rotation (TRFR) spectroscopies, in conjunction with continuous-wave absorption, magnetic circular dichroism (MCD), and magnetic circularly polarized photoluminescence (MCPL) spectroscopies. The data indicate that EMPs form with random magnetization orientations at zero external field, but their formation can be directed by an external magnetic field. After formation, however, external magnetic fields are unable to reorient the EMPs within the luminescence lifetime, implicating anisotropy in the EMP potential-energy surfaces. TRFR measurements in a transverse magnetic field reveal rapid (<5 ps) spin transfer from excitons to Mn(2+) followed by coherent EMP precession at the Mn(2+) Larmor frequency for over a nanosecond. A dynamical TRFR phase inversion is observed during EMP formation attributed to the large shifts in excitonic absorption energies during spontaneous magnetization. Partial optical orientation of the EMPs by resonant circularly polarized photoexcitation is also demonstrated. Collectively, these results highlight the extraordinary physical properties of colloidal diffusion-doped Cd(1-x)Mn(x)Se QDs that result from their unique combination of strong quantum confinement, large Mn(2+) concentrations, and relatively narrow size distributions. The insights gained from these measurements advance our understanding of spin dynamics and magnetic exchange in colloidal doped semiconductor nanostructures, with potential ramifications for future spin-based information technologies.
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Affiliation(s)
- Heidi D Nelson
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Liam R Bradshaw
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Charles J Barrows
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Vladimir A Vlaskin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
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21
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Barrows CJ, Vlaskin VA, Gamelin DR. Absorption and Magnetic Circular Dichroism Analyses of Giant Zeeman Splittings in Diffusion-Doped Colloidal Cd(1-x)Mn(x)Se Quantum Dots. J Phys Chem Lett 2015; 6:3076-3081. [PMID: 26267205 DOI: 10.1021/acs.jpclett.5b01137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Impurity ions can transform the electronic, magnetic, or optical properties of colloidal quantum dots. Magnetic impurities introduce strong dopant-carrier exchange coupling that generates giant Zeeman splittings (ΔEZ) of excitonic excited states. To date, ΔEZ in colloidal doped quantum dots has primarily been quantified by analysis of magnetic circular dichroism (MCD) intensities and absorption line widths (σ). Here, we report ΔEZ values detected directly by absorption spectroscopy for the first time in such materials, using colloidal Cd(1-x)Mn(x)Se quantum dots prepared by diffusion doping. A convenient method for decomposing MCD and absorption data into circularly polarized absorption spectra is presented. These data confirm the widely applied MCD analysis in the low-field, high-temperature regime, but also reveal a breakdown at low temperatures and high fields when ΔEZ/σ approaches unity, a situation not previously encountered in doped quantum dots. This breakdown is apparent for the first time here because of the extraordinarily large ΔEZ and small σ achieved by nanocrystal diffusion doping.
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Affiliation(s)
- Charles J Barrows
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Vladimir A Vlaskin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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22
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Kobak J, Smoleński T, Goryca M, Papaj M, Gietka K, Bogucki A, Koperski M, Rousset JG, Suffczyński J, Janik E, Nawrocki M, Golnik A, Kossacki P, Pacuski W. Designing quantum dots for solotronics. Nat Commun 2015; 5:3191. [PMID: 24463946 PMCID: PMC3916836 DOI: 10.1038/ncomms4191] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 01/02/2014] [Indexed: 01/28/2023] Open
Abstract
Solotronics, optoelectronics based on solitary dopants, is an emerging field of research and technology reaching the ultimate limit of miniaturization. It aims at exploiting quantum properties of individual ions or defects embedded in a semiconductor matrix. It has already been shown that optical control of a magnetic ion spin is feasible using the carriers confined in a quantum dot. However, a serious obstacle was the quenching of the exciton luminescence by magnetic impurities. Here we show, by photoluminescence studies on thus-far-unexplored individual CdTe dots with a single cobalt ion and CdSe dots with a single manganese ion, that even if energetically allowed, nonradiative exciton recombination through single-magnetic-ion intra-ionic transitions is negligible in such zero-dimensional structures. This opens solotronics for a wide range of as yet unconsidered systems. On the basis of results of our single-spin relaxation experiments and on the material trends, we identify optimal magnetic-ion quantum dot systems for implementation of a single-ion-based spin memory. Single-atom dopants embedded in a semiconductor matrix are of potential use for optical, spintronics as well as information storage applications. Here, Kobak et al. realize CdTe and CdSe quantum dots with single cobalt and manganese ions and show how the quantum dot design influences single-spin relaxation time.
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Affiliation(s)
- J Kobak
- 1] Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland [2]
| | - T Smoleński
- 1] Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland [2]
| | - M Goryca
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - M Papaj
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - K Gietka
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - A Bogucki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - M Koperski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - J-G Rousset
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - J Suffczyński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - E Janik
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - M Nawrocki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - A Golnik
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
| | - W Pacuski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoża 69, Warsaw 00-681, Poland
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23
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Goryca M, Koperski M, Wojnar P, Smoleński T, Kazimierczuk T, Golnik A, Kossacki P. Coherent Precession of an Individual 5/2 Spin. PHYSICAL REVIEW LETTERS 2014; 113:227202. [PMID: 25494084 DOI: 10.1103/physrevlett.113.227202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Indexed: 06/04/2023]
Abstract
We present direct observation of a coherent spin precession of an individual Mn^{2+} ion, having both electronic and nuclear spins equal to 5/2, embedded in a CdTe quantum dot and placed in a magnetic field. The spin state evolution is probed in a time-resolved pump-probe measurement of absorption of the single dot. The experiment reveals subtle details of the large-spin coherent dynamics, such as nonsinusoidal evolution of states occupation, and beatings caused by the strain-induced differences in energy levels separation. Sensitivity of the large-spin impurity on the crystal strain opens the possibility of using it as a local strain probe.
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Affiliation(s)
- M Goryca
- Institute of Experimental Physics, University of Warsaw, ul. Hoża 69, 00-681 Warszawa, Poland
| | - M Koperski
- Institute of Experimental Physics, University of Warsaw, ul. Hoża 69, 00-681 Warszawa, Poland
| | - P Wojnar
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-688 Warszawa, Poland
| | - T Smoleński
- Institute of Experimental Physics, University of Warsaw, ul. Hoża 69, 00-681 Warszawa, Poland
| | - T Kazimierczuk
- Institute of Experimental Physics, University of Warsaw, ul. Hoża 69, 00-681 Warszawa, Poland
| | - A Golnik
- Institute of Experimental Physics, University of Warsaw, ul. Hoża 69, 00-681 Warszawa, Poland
| | - P Kossacki
- Institute of Experimental Physics, University of Warsaw, ul. Hoża 69, 00-681 Warszawa, Poland
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24
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Krebs O, Lemaître A. Optically induced coupling of two magnetic dopant spins by a photoexcited hole in a Mn-doped InAs/GaAs quantum dot. PHYSICAL REVIEW LETTERS 2013; 111:187401. [PMID: 24237560 DOI: 10.1103/physrevlett.111.187401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/06/2013] [Indexed: 06/02/2023]
Abstract
We report evidence of a photoinduced coupling between two spins provided by Mn dopants in their neutral acceptor state A(0) in a single InAs/GaAs quantum dot. The coupling occurs due to simultaneous exchange interactions between each of the two dopant spins and a photocreated hole. Microphotoluminescence spectroscopy achieved both in longitudinal and perpendicular magnetic fields reveals the splitting of the four spin configurations |J(1) = ± 1,J(2) = ± 1} due to the 2A(0)-hole exchange interaction. We obtain a comprehensive interpretation of the experimental data with a simplified spin Hamiltonian model, which more specifically shows that the hole-mediated coupling is similar to a ε(12)-70 μeV exchange interaction between both A(0) spins.
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Affiliation(s)
- O Krebs
- CNRS-Laboratoire de Photonique et de Nanostructures, Route de Nozay, 91460 Marcoussis, France
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25
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Hazarika A, Layek A, De S, Nag A, Debnath S, Mahadevan P, Chowdhury A, Sarma DD. Ultranarrow and widely tunable Mn2+-Induced photoluminescence from single Mn-doped nanocrystals of ZnS-CdS alloys. PHYSICAL REVIEW LETTERS 2013; 110:267401. [PMID: 23848921 DOI: 10.1103/physrevlett.110.267401] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 02/22/2013] [Indexed: 06/02/2023]
Abstract
Extensively studied Mn-doped semiconductor nanocrystals have invariably exhibited photoluminescence over a narrow energy window of width ≤150 meV in the orange-red region and a surprisingly large spectral width (≥180 meV), contrary to its presumed atomic-like origin. Carrying out emission measurements on individual single nanocrystals and supported by ab initio calculations, we show that Mn PL emission, in fact, can (i) vary over a much wider range (∼370 meV) covering the deep green--deep red region and (ii) exhibit widths substantially lower (∼60-75 meV) than reported so far, opening newer application possibilities and requiring a fundamental shift in our perception of the emission from Mn-doped semiconductor nanocrystals.
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Affiliation(s)
- Abhijit Hazarika
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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26
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27
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Qu F, Moura FV, Alves FM, Gargano R. Optical tunability of magnetic polaron stability in single-Mn doped bulk GaAs and GaAs/AlGaAs quantum dots. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.01.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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28
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Kossut J. Diluted magnetic semiconductors. Copper joins the family. NATURE NANOTECHNOLOGY 2012; 7:774-775. [PMID: 23212418 DOI: 10.1038/nnano.2012.216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Magnetic circular dichroism on quantum dots doped with a small percentage of copper ions show the typical features of diluted magnetic semiconductors.
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Affiliation(s)
- Jacek Kossut
- Institute of Physics of the Polish Academy of Sciences, Warsaw, Poland.
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Manipulating Mn-Mgk cation complexes to control the charge- and spin-state of Mn in GaN. Sci Rep 2012; 2:722. [PMID: 23056914 PMCID: PMC3467566 DOI: 10.1038/srep00722] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/18/2012] [Indexed: 11/08/2022] Open
Abstract
Owing to the variety of possible charge and spin states and to the different ways of coupling to the environment, paramagnetic centres in wide band-gap semiconductors and insulators exhibit a strikingly rich spectrum of properties and functionalities, exploited in commercial light emitters and proposed for applications in quantum information. Here we demonstrate, by combining synchrotron techniques with magnetic, optical and ab initio studies, that the codoping of GaN:Mn with Mg allows to control the Mnn+ charge and spin state in the range 3≤n≤5 and 2≥S≥1. According to our results, this outstanding degree of tunability arises from the formation of hitherto concealed cation complexes Mn-Mgk, where the number of ligands k is pre-defined by fabrication conditions. The properties of these complexes allow to extend towards the infrared the already remarkable optical capabilities of nitrides, open to solotronics functionalities, and generally represent a fresh perspective for magnetic semiconductors.
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30
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Gong WJ, Han Y, Wei GZ, Du A. Spin accumulation assisted by the Aharonov-Bohm-Fano effect of quantum dot structures. NANOSCALE RESEARCH LETTERS 2012; 7:510. [PMID: 22985404 PMCID: PMC3564718 DOI: 10.1186/1556-276x-7-510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/20/2012] [Indexed: 06/01/2023]
Abstract
: We investigate the spin accumulations of Aharonov-Bohm interferometers with embedded quantum dots by considering spin bias in the leads. It is found that regardless of the interferometer configurations, the spin accumulations are closely determined by their quantum interference features. This is mainly manifested in the dependence of spin accumulations on the threaded magnetic flux and the nonresonant transmission process. Namely, the Aharonov-Bohm-Fano effect is a necessary condition to achieve the spin accumulation in the quantum dot of the resonant channel. Further analysis showed that in the double-dot interferometer, the spin accumulation can be detailedly manipulated. The spin accumulation properties of such structures offer a new scheme of spin manipulation. When the intradot Coulomb interactions are taken into account, we find that the electron interactions are advantageous to the spin accumulation in the resonant channel.
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Affiliation(s)
- Wei-Jiang Gong
- College of Sciences, Northeastern University, Shenyang, 110819, China
- International Centre for Materials Physics, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Yu Han
- Department of Physics, Liaoning University, Shenyang, 110036, China
| | - Guo-Zhu Wei
- College of Sciences, Northeastern University, Shenyang, 110819, China
- International Centre for Materials Physics, Chinese Academy of Sciences, Shenyang, 110016, China
| | - An Du
- College of Sciences, Northeastern University, Shenyang, 110819, China
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31
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Abolfath RM, Korkusinski M, Brabec T, Hawrylak P. Spin textures in strongly coupled electron spin and magnetic or nuclear spin systems in quantum dots. PHYSICAL REVIEW LETTERS 2012; 108:247203. [PMID: 23004315 DOI: 10.1103/physrevlett.108.247203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 02/20/2012] [Indexed: 06/01/2023]
Abstract
Controlling electron spins strongly coupled to magnetic and nuclear spins in solid state systems is an important challenge in the field of spintronics and quantum computation. We show here that electron droplets with no net spin in semiconductor quantum dots strongly coupled with magnetic ion or nuclear spin systems break down at low temperature and form a nontrivial antiferromagnetic spatially ordered spin texture of magnetopolarons. The spatially ordered combined electron-magnetic ion spin texture, associated with spontaneous symmetry breaking in the parity of electronic charge and spin densities and magnetization of magnetic ions, emerges from an ab initio density functional approach to the electronic system coupled with mean-field approximation for the magnetic or nuclear spin system. The predicted phase diagram determines the critical temperature as a function of coupling strength and identifies possible phases of the strongly coupled spin system. The prediction may arrest fluctuations in the spin system and open the way to control, manipulate, and prepare magnetic and nuclear spin ensembles in semiconductor nanostructures.
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Affiliation(s)
- Ramin M Abolfath
- School of Natural Sciences and Mathematics, University of Texas at Dallas, Richardson, Texas 75080, USA
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32
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Clavijo-Jordan V, Kodibagkar VD, Beeman SC, Hann BD, Bennett KM. Principles and emerging applications of nanomagnetic materials in medicine. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2012; 4:345-65. [PMID: 22488879 DOI: 10.1002/wnan.1169] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The development of nanometer-scale magnetic materials for biomedical applications spans the interface between the physical sciences and biology. Applications of these materials are rapidly becoming important in medicine and enable targeted therapies and diagnostics. At the same time, specific applications add focus to the development of novel magnetic materials and facilitate a deeper understanding of the physical mechanisms behind their function. This review presents a broad, nontechnical overview of the basis of magnetism in materials at the nanometer scale and describes how these materials are created, characterized, and used. Specific emerging applications in medical diagnostics and therapies are discussed, including cancer cell targeting for thermal ablation, tissue engineering, and three-dimensional noninvasive molecular imaging. Challenges in these fields are discussed, including the toxicity and delivery of magnetic nanomaterials and the sensitivity of imaging and therapeutic techniques. The development of novel nanomagnetic nanomaterials should continue to accelerate as new applications are identified and researchers uncover new mechanisms to increase and modulate magnetism at the nanometer scale.
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Affiliation(s)
- Veronica Clavijo-Jordan
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
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33
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Trojnar AH, Korkusiński M, Kadantsev ES, Hawrylak P, Goryca M, Kazimierczuk T, Kossacki P, Wojnar P, Potemski M. Quantum interference in exciton-Mn spin interactions in a CdTe semiconductor quantum dot. PHYSICAL REVIEW LETTERS 2011; 107:207403. [PMID: 22181774 DOI: 10.1103/physrevlett.107.207403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Indexed: 05/31/2023]
Abstract
We show theoretically and experimentally the existence of a new quantum-interference effect between the electron-hole interactions and the scattering by a single Mn impurity. The theoretical model, including electron-valence-hole correlations, the short- and long-range exchange interaction of a Mn ion with the heavy hole and with electron and anisotropy of the quantum dot, is compared with photoluminescence spectroscopy of CdTe dots with single magnetic ions. We show how the design of the electronic levels of a quantum dot enables the design of an exciton, control of the quantum interference, and hence engineering of light-Mn interaction.
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Affiliation(s)
- A H Trojnar
- Institute for Microstructural Sciences, National Research Council, Ottawa, Canada
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34
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Viswanatha R, Pietryga JM, Klimov VI, Crooker SA. Spin-polarized Mn2+ emission from Mn-doped colloidal nanocrystals. PHYSICAL REVIEW LETTERS 2011; 107:067402. [PMID: 21902367 DOI: 10.1103/physrevlett.107.067402] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Indexed: 05/31/2023]
Abstract
We report magnetophotoluminescence studies of strongly quantum-confined 0D diluted magnetic semiconductors (DMS), realized in Mn(2+)-doped ZnSe/CdSe core-shell colloidal nanocrystals. In marked contrast to their 3D (bulk), 2D (quantum well), 1D (quantum wire), and 0D (self-assembled quantum dot) DMS counterparts, the ubiquitous yellow emission band from internal d-d ((4)T(1)→(6)A(1)) transitions of the Mn(2+) ions in these nanocrystals is not suppressed in applied magnetic fields and does become circularly polarized. This polarization tracks the Mn(2+) magnetization, and is accompanied by a sizable energy splitting between right- and left-circular emission components that scales with the exciton-Mn sp-d coupling strength (which, in turn, is tunable with nanocrystal size). These data highlight the influence of strong quantum confinement on both the excitation and the emission mechanisms of magnetic ions in DMS nanomaterials.
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Affiliation(s)
- Ranjani Viswanatha
- Chemistry Division, Los Alamos National Laboratory, New Mexico 87545, USA
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35
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Le Gall C, Brunetti A, Boukari H, Besombes L. Optical stark effect and dressed exciton states in a Mn-doped CdTe quantum dot. PHYSICAL REVIEW LETTERS 2011; 107:057401. [PMID: 21867096 DOI: 10.1103/physrevlett.107.057401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Indexed: 05/31/2023]
Abstract
We report on the observation of spin-dependent optically dressed states and the optical Stark effect on an individual Mn spin in a semiconductor quantum dot. The vacuum-to-exciton or the exciton-to-biexciton transitions in a Mn-doped quantum dot are optically dressed by a strong laser field, and the resulting spectral signature is measured in photoluminescence. We demonstrate that the energy of any spin state of a Mn atom can be independently tuned by using the optical Stark effect induced by a control laser. High resolution spectroscopy reveals a power-, polarization-, and detuning-dependent Autler-Townes splitting of each optical transition of the Mn-doped quantum dot. This experiment demonstrates an optical resonant control of the exciton-Mn system.
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Affiliation(s)
- C Le Gall
- CEA-CNRS group Nanophysique et semiconducteurs, Institut Néel, CNRS and Université Joseph Fourier, B.P. 166, F-38042 Grenoble Cedex 9, France
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36
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Andrade JA, Aligia AA, Quinteiro GF. Spin-spin indirect interaction at low-energy excitation in zero-dimensional cavities. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:215304. [PMID: 21555830 DOI: 10.1088/0953-8984/23/21/215304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We solve the low-energy part of the spectrum of a model that describes a circularly polarized cavity mode strongly coupled to two exciton modes, each of which is coupled to a localized spin of arbitrary magnitude. In the regime in which the excitons and the cavity modes are strongly coupled, forming polaritons, the low-energy part of the spectrum can be described by an effective spin model, which contains a magnetic field, an axial anisotropy, and an Ising interaction between the localized spins. For detunings such that the low-energy states are dominated by nearly degenerate excitonic modes, the description of the low-energy states by a simple effective Hamiltonian ceases to be valid and the effective interaction tends to vanish. Finally, we discuss a possible application to two-qubit quantum computing operations in a system of transition-metal impurities embedded in quantum dots inside a micropillar.
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Affiliation(s)
- J A Andrade
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, Bariloche, Argentina
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37
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Oszwałdowski R, Zutić I, Petukhov AG. Magnetism in closed-shell quantum dots: emergence of magnetic bipolarons. PHYSICAL REVIEW LETTERS 2011; 106:177201. [PMID: 21635058 DOI: 10.1103/physrevlett.106.177201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Indexed: 05/30/2023]
Abstract
Similar to atoms and nuclei, semiconductor quantum dots exhibit the formation of shells. Predictions of magnetic behavior of the dots are often based on the shell occupancies. Thus, closed-shell quantum dots are assumed to be inherently nonmagnetic. Here, we propose a possibility of magnetism in such dots doped with magnetic impurities. On the example of the system of two interacting fermions, the simplest embodiment of the closed-shell structure, we demonstrate the emergence of a novel broken-symmetry ground state that is neither spin singlet nor spin triplet. We propose experimental tests of our predictions and the magnetic-dot structures to perform them.
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Affiliation(s)
- Rafał Oszwałdowski
- Department of Physics, University at Buffalo, Buffalo, New York 14260-1500, USA
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38
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Akimov IA, Dzhioev RI, Korenev VL, Kusrayev YG, Sapega VF, Yakovlev DR, Bayer M. Optical orientation of Mn2+ ions in GaAs in weak longitudinal magnetic fields. PHYSICAL REVIEW LETTERS 2011; 106:147402. [PMID: 21561222 DOI: 10.1103/physrevlett.106.147402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Indexed: 05/30/2023]
Abstract
We report on optical orientation of Mn2+ ions in bulk GaAs subject to weak longitudinal magnetic fields (B≤100 mT). A manganese spin polarization of 25% is directly evaluated by using spin-flip Raman scattering. The dynamical Mn2+ polarization occurs due to the s-d exchange interaction with optically oriented conduction band electrons. Time-resolved photoluminescence reveals a nontrivial electron spin dynamics, where the oriented Mn2+ ions tend to stabilize the electron spins.
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Affiliation(s)
- I A Akimov
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
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39
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Abstract
The sensitive dependence of a semiconductor's electronic, optical and magnetic properties on dopants has provided an extensive range of tunable phenomena to explore and apply to devices. Recently it has become possible to move past the tunable properties of an ensemble of dopants to identify the effects of a solitary dopant on commercial device performance as well as locally on the fundamental properties of a semiconductor. New applications that require the discrete character of a single dopant, such as single-spin devices in the area of quantum information or single-dopant transistors, demand a further focus on the properties of a specific dopant. This article describes the huge advances in the past decade towards observing, controllably creating and manipulating single dopants, as well as their application in novel devices which allow opening the new field of solotronics (solitary dopant optoelectronics).
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Affiliation(s)
- Paul M Koenraad
- COBRA Inter-University Research Institute, Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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40
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Ochsenbein ST, Gamelin DR. Quantum oscillations in magnetically doped colloidal nanocrystals. NATURE NANOTECHNOLOGY 2011; 6:112-5. [PMID: 21170039 DOI: 10.1038/nnano.2010.252] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 11/17/2010] [Indexed: 05/18/2023]
Abstract
Progress in the synthesis of colloidal quantum dots has recently provided access to entirely new forms of diluted magnetic semiconductors, some of which may find use in quantum computation. The usefulness of a spin qubit is defined by its Rabi frequency, which determines the operation time, and its coherence time, which sets the error correction window. However, the spin dynamics of magnetic impurity ions in colloidal doped quantum dots remain entirely unexplored. Here, we use pulsed electron paramagnetic resonance spectroscopy to demonstrate long spin coherence times of ∼0.9 µs in colloidal ZnO quantum dots containing the paramagnetic dopant Mn(2+), as well as Rabi oscillations with frequencies ranging between 2 and 20 MHz depending on microwave power. We also observe electron spin echo envelope modulations of the Mn(2+) signal due to hyperfine coupling with protons outside the quantum dots, a situation unique to the colloidal form of quantum dots, and not observed to date.
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Affiliation(s)
- Stefan T Ochsenbein
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
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41
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42
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Manaselyan A, Chakraborty T. Spin interactions in a quantum dot containing a magnetic impurity. NANOTECHNOLOGY 2010; 21:355401. [PMID: 20689166 DOI: 10.1088/0957-4484/21/35/355401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The electron and hole states in a CdTe quantum dot containing a single magnetic impurity in an external magnetic field are investigated using a multiband approximation which includes the heavy hole-light hole coupling effects. The electron-hole spin interactions and sp-d interactions between the electron, the hole and the magnetic impurity are also included. The exciton energy levels and optical transitions are evaluated using the exact diagonalization scheme. A novel mechanism is proposed here to manipulate impurity spin in the quantum dot which allows us to drive selectively the spin of the magnetic atom into each of its six possible orientations.
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Affiliation(s)
- Aram Manaselyan
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Canada
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43
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Manfredi G, Hervieux PA, Yin Y, Crouseilles N. Collective Electron Dynamics in Metallic and Semiconductor Nanostructures. ADVANCES IN THE ATOMIC-SCALE MODELING OF NANOSYSTEMS AND NANOSTRUCTURED MATERIALS 2010. [DOI: 10.1007/978-3-642-04650-6_1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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44
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Diluted Magnetic Quantum Dots. INTRODUCTION TO THE PHYSICS OF DILUTED MAGNETIC SEMICONDUCTORS 2010. [DOI: 10.1007/978-3-642-15856-8_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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45
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Reiter DE, Kuhn T, Axt VM, Machnikowski P. Dynamics of a single Mn spin in a quantum dot: The role of magnetic fields in Faraday and Voigt geometry. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/193/1/012101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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46
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Zutić I, Petukhov A. Spintronics: Shedding light on nanomagnets. NATURE NANOTECHNOLOGY 2009; 4:623-625. [PMID: 19809449 DOI: 10.1038/nnano.2009.286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Igor Zutić
- Department of Physics, State University of New York at Buffalo, Buffalo, New York 14260, USA.
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47
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Ochsenbein ST, Feng Y, Whitaker KM, Badaeva E, Liu WK, Li X, Gamelin DR. Charge-controlled magnetism in colloidal doped semiconductor nanocrystals. NATURE NANOTECHNOLOGY 2009; 4:681-7. [PMID: 19809461 DOI: 10.1038/nnano.2009.221] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 07/09/2009] [Indexed: 05/22/2023]
Abstract
Electrical control over the magnetic states of doped semiconductor nanostructures could enable new spin-based information processing technologies. To this end, extensive research has recently been devoted to examination of carrier-mediated magnetic ordering effects in substrate-supported quantum dots at cryogenic temperatures, with carriers introduced transiently by photon absorption. The relatively weak interactions found between dopants and charge carriers have suggested that gated magnetism in quantum dots will be limited to cryogenic temperatures. Here, we report the observation of a large, reversible, room-temperature magnetic response to charge state in free-standing colloidal ZnO nanocrystals doped with Mn(2+) ions. Injected electrons activate new ferromagnetic Mn(2+)-Mn(2+) interactions that are strong enough to overcome antiferromagnetic coupling between nearest-neighbour dopants, making the full magnetic moments of all dopants observable. Analysis shows that this large effect occurs in spite of small pairwise electron-Mn(2+) exchange energies, because of competing electron-mediated ferromagnetic interactions involving distant Mn(2+) ions in the same nanocrystal.
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Affiliation(s)
- Stefan T Ochsenbein
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
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48
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Goryca M, Kazimierczuk T, Nawrocki M, Golnik A, Gaj JA, Kossacki P, Wojnar P, Karczewski G. Optical manipulation of a single Mn spin in a CdTe-based quantum dot. PHYSICAL REVIEW LETTERS 2009; 103:087401. [PMID: 19792759 DOI: 10.1103/physrevlett.103.087401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Indexed: 05/28/2023]
Abstract
Two coupled CdTe quantum dots, selected from a self-assembled system, one of them containing a single Mn ion, were studied by continuous wave and modulated photoluminescence, photoluminescence excitation, and photon correlation experiments. Optical writing of information on the spin state of the Mn ion has been demonstrated, using the orientation of the Mn spin by spin-polarized carriers transferred from the neighboring quantum dot. Mn spin orientation time values from 20 to 100 ns were measured, depending on the excitation power. Storage time of the information on the Mn spin was found to be enhanced by application of a static magnetic field of 1 T, reaching hundreds of microseconds in the dark. Simple rate equation models were found to describe correctly the static and dynamical properties of the system.
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Affiliation(s)
- M Goryca
- Institute of Experimental Physics, University of Warsaw, Hoza 69, 00-681 Warsaw, Poland.
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49
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Reiter DE, Kuhn T, Axt VM. All-optical spin manipulation of a single manganese atom in a quantum dot. PHYSICAL REVIEW LETTERS 2009; 102:177403. [PMID: 19518830 DOI: 10.1103/physrevlett.102.177403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Indexed: 05/27/2023]
Abstract
For a CdTe quantum dot doped with a single Mn atom we analyze the dynamics of the Mn spin when the dot is excited by ultrashort laser pulses. Because of the exchange interaction with the Mn atom, electron and hole spins can flip and induce a change of the Mn spin. Including both heavy and light-hole excitons and using suitable pulse sequences, angular momentum can be transferred from the light to the Mn system while the exciton system returns to its ground state. We show that by a series of ultrashort laser pulses the Mn spin can be selectively driven into each of its six possible orientations on a picosecond timescale. By applying a magnetic field the total switching time and the required number of pulses can be strongly reduced.
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Affiliation(s)
- D E Reiter
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany
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50
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Le Gall C, Besombes L, Boukari H, Kolodka R, Cibert J, Mariette H. Optical spin orientation of a single manganese atom in a semiconductor quantum dot using quasiresonant photoexcitation. PHYSICAL REVIEW LETTERS 2009; 102:127402. [PMID: 19392322 DOI: 10.1103/physrevlett.102.127402] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Indexed: 05/27/2023]
Abstract
An optical spin orientation is achieved for a Mn atom localized in a semiconductor quantum dot using quasiresonant excitation at zero magnetic field. Optically created spin-polarized carriers generate an energy splitting of the Mn spin and enable magnetic moment orientation controlled by the photon helicity and energy. The dynamics and the magnetic field dependence of the optical pumping mechanism show that the spin lifetime of an isolated Mn atom at zero magnetic field is controlled by a magnetic anisotropy induced by the built-in strain in the quantum dots.
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Affiliation(s)
- C Le Gall
- Université Joseph Fourier, 38042 Grenoble, France
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